Virtualize with lithops

[abarciauskas-bgse]

This PR adds a script and documentation to create an icechunk virtual store using lithops.

cc @jbusecke

[espg]

@abarciauskas-bgse , can you update the gs://ismip6-icechunk bucket to allow anonymous access? Right now the following fails:

icechunk_storage = icechunk.gcs_storage(
    bucket="ismip6-icechunk",
    prefix="12-07-2025",
    anonymous=True
)

I tried testing on a jupyterhub instance, and haven't had a chance to setup with Google Cloud SDK (gcloud) installed and configured for providing with gcloud credentials provisioned using from_env=True yet. But I anticipate that when we set this pipeline up, we'll want the access pattern to allow for non-credentialed / anonymous access.

[abarciauskas-bgse]

@espg yes I agree, this anonymous access should work. I'm looking into the org-level policies that may be preventing this and should hopefully have it fixed soon!

[abarciauskas-bgse]

@espg could you try again now? A few of us have tested with anonymous=True and opening and reading from the store appears to be working via anonymous access.